High impact information on LOC443413

• Modulation of GnRH receptor mRNA levels suggests that IN, E, and P regulate responsiveness to GnRH in the ovine pituitary at least in part by altering de novo synthesis of GnRH receptors [1].
• The experimental paradigm comprised graded blockade of the GnRH receptor to create four distinct strata of LH and Te pulsatility in each subject [2].
• Treatment with estradiol caused an increase in concentrations of GnRH receptor mRNA (P < 0.05) and GnRH receptors (P < 0.01) [3].
• To explore the regulation of GnRH receptors at the level of gene expression, a partial complementary DNA (cDNA) encoding ovine GnRH receptor was isolated using reverse transcription and polymerase chain reaction methodology [4].
• Concentrations of GnRH receptor mRNA increased 2-fold during luteolysis and were higher than control values 12 h after PGF2 alpha treatment (P < 0.05) [4].

Biological context of LOC443413

• This partial cDNA (701 basepairs) was used to isolate a full-length cDNA encoding GnRH receptor from an ovine pituitary cDNA library [4].
• GnRH-receptor interaction. V. Down-regulation of pituitary receptors for GnRH in ovariectomized ewes by infusion of homologous hormone [5].
• Are immediate early genes involved in gonadotropin-releasing hormone receptor gene regulation? Characterization of changes in GnRH receptor (GnRH-R), c-fos, and c-jun messenger ribonucleic acids during the ovine estrous cycle [6].
• These results provide evidence that the stimulatory effects of oestradiol on the expression of the GnRH receptor gene are prevented during the natural luteal phase in ewes [7].
• The objective of this experiment was to determine the extent to which low levels of estradiol, similar to those observed during the transition from the luteal to the follicular phase of the estrous cycle, and GnRH interact to regulate expression of GnRH receptors and GnRH receptor mRNA [8].

Anatomical context of LOC443413

• Pituitary glands were collected from fourteen 20-wk-old ram lambs from each line, weighed, and sampled for GnRH receptor analysis [9].
• As circulating concentrations of progesterone decrease during the early preovulatory period, concentrations of mRNA encoding ovine GnRH receptor in the anterior pituitary gland increase [10].
• It remains to be confirmed whether the major effect is at the pituitary by reducing GnRH receptor or LH synthesis, or at the hypothalamus via inhibition of GnRH secretion [11].
• The present study characterized the expression of GnRH and GnRH receptor (GnRH-R) in sheep spinal cord using real-time PCR and immunocytochemistry [12].

Associations of LOC443413 with chemical compounds

• After 48 h of treatment, IN or E each led to a 7- to 8-fold increase in GnRH receptor mRNA activity [1].
• We hypothesized that during luteolysis, decreased concentrations of progesterone would be associated with increased concentrations of GnRH receptor mRNA and increased numbers of GnRH receptors [4].
• The effect of stress-like concentrations of cortisol (C) on estrogen-dependent expression of GnRH receptor was evaluated using orchidectomized sheep (wethers; n = 6 animals per group) [13].
• Conversely, concurrent progestin stimulation potentiated the E2-induced augmentation of tissue concentrations of GnRH receptor [14].

Physical interactions of LOC443413

• Estradiol and gonadotropin-releasing hormone (GnRH) interact to increase GnRH receptor expression in ovariectomized ewes after hypothalamic-pituitary disconnection [8].

Other interactions of LOC443413

• In contrast, ewes treated with continuous GnRH (2.5 micrograms h-1) demonstrated LH secretory patterns indicative of GnRH receptor downregulation on day 1 of treatment [15].

Analytical, diagnostic and therapeutic context of LOC443413

• Passive immunization against GnRH increased (p less than 0.05) tissue stores of LH, but had no effect on GnRH receptor concentration [16].
• No differences in concentrations of GnRH receptor mRNA, numbers of GnRH receptors, or circulating concentrations of progesterone or estradiol were detected between groups of animals at 0 h and 24 h after treatment with saline; therefore, data from these control groups were combined [10].

References